1. Field of the Invention
The present invention relates to oral compositions for the delivery of pharmacologically active agents, to methods of enhancing the bioavailability of orally administered pharmacologically active agents, and to methods of treating and/or preventing disease in mammals, particularly humans, by orally administering a pharmacologically active agent in accordance with the invention.
2. Description of the Related Art
Oral delivery of pharmacologically active agents is generally the delivery route of choice since it is convenient, relatively easy and generally painless, resulting in greater patient compliance relative to other modes of delivery. However, biological, chemical and physical barriers such as varying pH in the gastrointestinal tract, powerful digestive enzymes, and active agent impermeable gastrointestinal membranes, makes oral delivery of some pharmacologically active agents to mammals problematic, e.g. the oral delivery of calcitonins, which are long-chain polypeptide hormones secreted by the parafollicular cells of the thyroid gland in mammals and by the ultimobranchial gland of birds and fish, has proven difficult due, at least in part, to the insufficient stability of calcitonin in the gastrointestinal tract as well as the inability of calcitonin to be readily transported through the intestinal walls into the blood stream.
U.S. Pat. Nos. 5,773,647 and 5,866,536 describe compositions for the oral delivery of active agents, such as heparin and calcitonin, with modified amino acids, such as, N-(5-chlorosalicyloyl)-8-aminocaprylic acid (5-CNAC), N-(10-[2-hydroxybenzoyl]aminodecanoic acid (SNAD), and N-(8-[2-hydroxybenzoyl]amino)caprylic acid (SNAC) In addition, WO 00/059863 discloses the disodium salts of formula I
wherein
R1, R2, R3, and R4 are independently hydrogen, —OH, —NR6R7, halogen, C1–C4alk C1–C4alkoxy;                R5 is a substituted or unsubstituted C2-C16alkylene, substituted or unsubstituted C2–C16alkenylene, substituted or unsubstituted C1–C12alkyl(arylene), or substituted or unsubstituted aryl(C1–C12alkylene); and        R6 and R7 are independently hydrogen, oxygen, or C1–C4 alkyl; and hydrates and solvates thereof as particularly efficacious for the oral delivery of active agents, such as calcitonin, cyclosporin and heparin.        
The present invention describes pharmaceutical compositions which provide still greater oral bioavailability of pharmacologically active agents, e.g. peptides such as calcitonin.